C 中的返回值优化和复制省略

Some people are not aware that it's possible to pass and return structs by value in C. My question is about the compiler making unnecessary copies when returning structs in C. Do C compilers such as GCC use Return value optimization(RVO) optimization or is this a C++ only concept? Everything I have read about RVO and copy elision is in regards to C++.

让我们考虑一个例子.我目前正在 C 中实现 双双数据类型(或者更确切地说是 float-float 开始，因为我发现单元测试很容易).考虑以下代码.

typedef struct {
    float hi;
    float lo;
} doublefloat;

doublefloat quick_two_sum(float a, float b) {
    float s = a + b;
    float e = b - (s - a);
    return (doublefloat){s, e};
}

doublefloat df64_add(doublefloat a, doublefloat b) {
    doublefloat s, t;
    s = two_sum(a.hi, b.hi);
    t = two_sum(a.lo, b.lo);
    s.lo += t.hi;
    s = quick_two_sum(s.hi, s.lo);
    s.lo += t.lo;
    s = quick_two_sum(s.hi, s.lo);
    return s;
}